On Mon, May 28, 2018 at 12:54 PM, Michael Nazzareno Trimarchi <michael@xxxxxxxxxxxxxxxxxxxx> wrote: > Hi Arend > > On Mon, May 28, 2018 at 11:51 AM, Arend van Spriel > <arend.vanspriel@xxxxxxxxxxxx> wrote: >> On 5/28/2018 9:50 AM, Michael Trimarchi wrote: >>> >>> Watchdog need to be stopped in brcmf_sdio_remove to avoid >>> i >>> The system is going down NOW! >>> [ 1348.110759] Unable to handle kernel NULL pointer dereference at virtual >>> address 000002f8 >>> Sent SIGTERM to all processes >>> [ 1348.121412] Mem abort info: >>> [ 1348.126962] ESR = 0x96000004 >>> [ 1348.130023] Exception class = DABT (current EL), IL = 32 bits >>> [ 1348.135948] SET = 0, FnV = 0 >>> [ 1348.138997] EA = 0, S1PTW = 0 >>> [ 1348.142154] Data abort info: >>> [ 1348.145045] ISV = 0, ISS = 0x00000004 >>> [ 1348.148884] CM = 0, WnR = 0 >>> [ 1348.151861] user pgtable: 4k pages, 48-bit VAs, pgdp = (____ptrval____) >>> [ 1348.158475] [00000000000002f8] pgd=0000000000000000 >>> [ 1348.163364] Internal error: Oops: 96000004 [#1] PREEMPT SMP >>> [ 1348.168927] Modules linked in: ipv6 >>> [ 1348.172421] CPU: 3 PID: 1421 Comm: brcmf_wdog/mmc0 Not tainted >>> 4.17.0-rc5-next-20180517 #18 >>> [ 1348.180757] Hardware name: Amarula A64-Relic (DT) >>> [ 1348.185455] pstate: 60000005 (nZCv daif -PAN -UAO) >>> [ 1348.190251] pc : brcmf_sdiod_freezer_count+0x0/0x20 >>> [ 1348.195124] lr : brcmf_sdio_watchdog_thread+0x64/0x290 >> >> >> Hi Michael, >> >> Thanks for the patch. In normal scenario the callstack looks like this: >> >> brcmf_sdio_remove() >> -> brcmf_detach() >> -> brcmf_bus_stop() >> -> brcmf_sdio_bus_stop() >> >> In brcmf_sdio_bus_stop() the watchdog is terminated. So in what scenario did >> you encounter this null pointer deref? > > Is this happen even when there is not wifi firmware? > boot without any firmware in the filesystem and then trigger a reboot Something like the above I had noticed for a long (couple of kernel releases?) time, but wasn't a big priority to me. Though, I can test this on my side. P.S. I think rmmod or echo > unbind will trigger that as well. -- With Best Regards, Andy Shevchenko
